Downloading of software programs

ABSTRACT

The invention relates to a receiver [STB] intended to process at least one content [p] sent by a transmission station over a netowrk [NET] including transportation channels configured for transporting said content, characterized in that it can be connected during so-called supply events on a so-called program channel [PGC] belonging to said network [NET]. The program transportation channel [PGC] conveys according to the invention at least one content [P(SW)] including at least one software programs [SW], intended to control the receiver, coded and in a loop. The receiver [STB] is connected [CNX] to said program channel [PGC], reads and decodes [DEC] and stores said software program [SW] in a volatile memory [VME]. Control means [CNT] controlled by a so-called supply program [SPG] stored in a non-volatile memory [NVM] control the connection [CNX] of the receiver [STB] to the program channel [PGC], the reading and decoding [DEC] and the storing [STR] of the software programs [SW].

The invention relates to a receiver intended to process at least onecontent sent by a transmission station via a network includingtransportation channels configured to transport said content. Inparticular, the invention relates to the transportation and downloadingof software programs on said network.

Document U.S. Pat. No. 5,790,753 describes a receiver of this typeintended to decode video contents, as well as software programsdownloaded from a transmission station. According to this document, thedownloading is performed at the request of the receiver, which sends arequest message to the transmission station over a bidirectionalcommunication channel between said receiver and said transmissionstation. This bidirectional channel requires, in addition to its own useby a data transmission means, means of generating requests within thereceiver to the network and to the transmission station, means ofreceiving and processing these requests within the transmission station,means for the selective transmission of the software program or programsto the electronic apparatus by means of which a request was sent, meansof checking errors in the software program actually downloaded in thereceiver, and means of reiterating the request in the case where thesoftware program downloaded is erroneous. This return channel also makesit possible, in one advantageous implementation, to update a softwareprogram on questioning of the transmission station by the receiver. Thereceiver sends a message over the return channel by questioning thetransmission station on the version of the software available, and thetransmission station compares the software versions and sends a newversion of the software if such is available. The downloading methodproposed in the document cited is a method based essentially on sendingsof data on request from the receiver to the latter.

The invention relates to the following considerations:

The sum of the means necessary for using the return channel and thedownloading on request gives rise to not insignificant costs, inparticular when it is wished to have a return channel by cable modem,which constitutes an expensive item of equipment with specific andexpensive components (tuner etc). These costs are in particulargenerated at the receiver intended to process the various contents andhaving a facility for downloading software programs. Electronicapparatus of this type is therefore particularly expensive. This isprejudicial on some markets in which the consumers assess the advantagesafforded by such electronic apparatus as being too small compared withthe cost price.

One aim of the invention is to greatly reduce the cost of suchelectronic apparatus by proposing a receiver with a lightweight andlow-cost structure and a transmission station, downloading method andsignal compatible with said receiver.

In fact a secure data processing system is characterized according tothe invention in that it includes:

-   -   connection means for making a connection, when so-called supply        events occur, with at least one so-called program transportation        channel, the program transportation channel transporting a        content including a continuous stream of data coming from said        transmission station, said data including at least one software        program, intended to control said receiver, coded in a loop,        from the transmission station to said receiver,    -   means of decoding said continuous stream of data in order to        decode the software program,    -   storage means including at least one volatile memory for storing        said software program,    -   means of controlling the connection, decoding and storage means        controlled by a so-called supply program stored in a        non-volatile memory.

The receiver proposed in combination with a transmission station and asignal transmitted over the program transportation channel bothcompatible with its functioning makes it possible to avoid the costsrelating to the implementation of a return channel and the sending ofdata on request from the receiver. The saving is achieved both withinthe receiver itself and within the transmission station. According tothe invention, when a so-called supply event occurs, for example a userwho connects his receiver, the receiver is connected to the programtransportation channel and can thus recover a software program, intendedto control it, over a program transportation channel of the networkwithout any other expensive operation. The speed of downloading dependson the bandwidth allocated for the software downloading by the operator.The supply events can for example be the connection of the receiver tothe supply mains or the start or end of a standby period, or a signalcoming from the transmission station to supply the receiver with a newsoftware program or a new version of a software program. The supplyprogram includes special instructions for making the means ofconnection, decoding and storage of the data stream function differentlyon the supply network according to the various events possible.

In an advantageous application of the invention, the receiver is suchthat at least one content is a content including video and/or audiodata, said receiver being intended to be connected to an apparatus forexploiting said data. This exploitation apparatus may for example be atelevision receiver. This is the case in particular with set-top boxes,decoding/receiving boxes separate from a receiver/final user of thedecoded data.

In an advantageous embodiment of the invention, the receiver alsoincludes means for managing conditional access information receivedamongst the data transmitted by the network to said receiver, saidconditional access information acting on said control means in order toenable or not the functioning of the decoding means for at least onecontent including a software program transported over said programtransportation channel. This embodiment is particularly useful when thenetwork continuously and permanently sends several software packages, oreven several software versions, over one or more program transportationchannels. The various software packages may for example correspond todifferent functionalities intended to function in a receiver accordingto the invention in order to control it. These different functionalitiesmay not be essential to a basic functioning of the receiver and may forexample be sold as options. The various software versions may, forexample, correspond to improvements having additional functionalities towhich access may also be obligatory (updating of all the receivers) oroptional. In the case of optional software and versions, for examplesold at a price higher than a basic version of an item of software,management of accesses according to the advantageous embodiment isuseful.

In a preferred embodiment of the invention, the only non-volatile memorypresent within the receiver is the one which includes the supply programand the downloaded software programs include the application softwareprograms necessary, within the receiver, for the processing of a contentsent by the transmission station. This has the effect of making itpossible to obtain a receiver which contains the minimum of non-volatilememory, which is expensive. According to the invention, the so-calledapplication software programs essential to the functioning of thereceiver are permanently available on said program transportationchannel in order to be downloaded and stored in a less expensivevolatile memory in order to be used by processing means and within theseto allow the processing of at least one content distinct from the onepresent on the program transportation channel and sent by thetransmission channel.

The invention also relates to a signal including digital data, intendedto be transported on a so-called program transportation channel from atransmission station to at least one receiver, characterized in thatsaid digital data comprise at least one content including a softwareprogram, intended to control said receiver, sent coded and in a loop(e.g. in a repetitive way) by said transmission station. The inventionalso relates to said transmission station, a downloading method and a“computer program” product used in a receiver according to theinvention.

The invention will be further described with reference to examples ofembodiments shown in the drawings to which, however, the invention isnot restricted.

FIG. 1 is a schematic diagram of an example of a network of cabledreceiving boxes in which the invention finds an application,

FIG. 2 is a schematic diagram of a receiver according to the invention,

FIG. 3 is a schematic diagram of a method according to the invention,

FIG. 4 is a schematic diagram of a transmission station according to theinvention.

The following remarks concern the reference signs. Similar entities aredesignated by identical letters in all the Figures. Several similarentities may appear in a single Figure. In this case, a digit or asuffix is added to the reference by letters in order to distinguishsimilar entities. The digit or suffix may be omitted for reasons ofconvenience. This applies to the description and to the claims.

The following description is presented to enable a person skilled in theart to implement and make use of the invention. This description isprovided in the context of the patent application and its requirements.Various alternatives to the preferred embodiment will be obvious to aperson skilled in the art and the generic principles of the inventiondisclosed here can be applied to other uses. Thus the present inventionis not deemed to be limited to the embodiment described but rather tohave the widest scope in accordance with the principles andcharacteristics described below.

FIG. 1 is a schematic diagram of an example of a cabled network ofreceiving boxes or receivers within which the invention canadvantageously be applied. It should be noted here that this Figure isonly indicative of a special application of the invention where thereceiving boxes are cabled. At least one data sender BP offers a contentp. The term sender is here used for defining any entity which producescontent and/or which makes a content compatible with the distribution:for example, a television studio which produces contents in televisionprogram form. The term may refer either to a technical receiver by whichthe content is sent or to a legal or commercial entity associated withthe content. The term content p is here used for defining data which canbe used in practice within a receiver: this will for example be audioand/or video data (a television program for example), interactive data,computer software programs, data associated with particular softwareprograms or other types of data. This sender BP is connected to atransmission station HES which makes it possible to send data in acertain transportation format over a network consisting oftransportation means NET. In the digital television applications whichparticularly relate to the invention, the transportation format is forexample in accordance with the MPEG standard. Any other standard used indigital television or in transportation of digital data can be usedaccording to the invention. According to FIG. 1, this transmissionstation is for example the head transmission station of a cabletelevision network and the transmission means NET consist of a cable.This is only one example, and the transmission station and thetransportation means NET may be various: radio network, telephoneconnection, network connection (Internet for example), a satellite, inwhich case the transmission station HES is a network operation center ofa satellite transmission system etc. Other senders of contents can beconnected to this transmission station HES in the same way as the senderBP. The transmission station HES has in particular a role ofmultiplexing the various contents P and of adding supplementaryconditional access information AC[n,p] in the data stream according tothe authorizations for access to the various contents sent by saidtransmission station granted to one or more receiving boxes STB[n] towhich a content p can be sent. This addition of supplementaryinformation is carried out by means of a database intended for managingrights of the users RMD. This addition is periodic, the periods ofinsertion of this information being variable. Thus this supplementaryinformation AC[n,p] serves for the conditional management of accesses.It is for example messages according to the EMM (“Entitlement ManagementMessages”) and ECM (“Entitlement Control Messages”) standards or anyother message using an identifier for the receiving boxes STB. Thetransmission station also in general has a role of scrambling certainparticular contents. For simplification, the scrambling effected ingeneral on, for example, the video and/or audio contents is notpresented. This is because this scrambling functions in parallel to theinvention without interacting with it. Only the coding of certainparticular contents according to the invention will be discussed morefully. According to FIG. 1, various user receiving boxes STB areconnected by transportation means NET to the transmission station HES.Whatever the transportation means (cable etc), the principles ofconnection between the receiving boxes STB and the transmission stationHES are similar and known from the state of the art. A connectionaccording to the state of the art can therefore be used for implementingthe invention. The use of the transportation means will however bedifferent according to the characteristics described below and peculiarto the invention. The data stream is transmitted to the variousreceiving boxes STB by said transportation means NET. Said receivingboxes STB conventionally include memories where software programs arestored for permitting the management of the processing of the contents.Such software programs are referred to as application software programshereinafter. These software programs refer to all kinds of softwareprograms which can advantageously be used in a receiving box STB forcontrolling the processing of data included in the content or contentsaccording to certain functionalities which the receiver may haveoccasion to implement: decoding etc.

FIG. 2 is a schematic diagram of a receiving/decoding box according tothe invention. The various elements of the receiving box or receiverwill now be described in terms of functional units. Thereceiving/decoding box, which can advantageously be a digital receivingbox for digital television, known in general as a “set-top box”,includes a central processor CPU connected to non-volatile memoryelements NVM, and volatile memory elements VME and means EXP ofprocessing contents received. The non-volatile memories may be FLASHmemories, ROM memories, or EEPROM memories, and the volatile memoriesare generally RAM memories. These memories contain data and programs formaking the CPU function according to the functionalities of thereceiver, and in particular they may include application programs. Thecentral processor CPU is also generally adapted for receiving data frominterfaces I, which may be serial interfaces, parallel interfaces, amodem, control elements placed on an external face of the receiving boxand on a remote control connected to a control unit, readers for variousmedia etc. A receiving box according to the invention can in particularcomprise one or more smart card readers which make it possible to addfunctionalities and/or flexible and modular conditional access controls(payment per session for example). The means of processing receivedcontents EXP include in general means for selecting the contents(tuner), means of demodulating the stream of data transmitted by thetransportation means and means for the data stream to be filtered,demultiplexed and decoded within said processing means. These processingmeans use in particular many kinds of software programs for fulfillingin particular the functions of filtering, decoding, unscrambling,demultiplexing etc disclosed above. Any software program making itpossible to perform the content processing operations disclosed above isreferred to as an application software program. According to theinvention, these processing means can therefore be controlled or evenimplemented by at least one such application software program stored inthe volatile memory VME during the functioning of a method according tothe invention. For example, a receiver/decoder according to theinvention includes application software programs downloaded and storedin memory, for processing and using the contents p distinct from thecontent or contents including said software programs, so as to convertthem, for example, into video output data VO and/or audio output data AOwhich can be used for example in an apparatus for exploiting the dataREC. This exploitation apparatus will for example be a television set.The structures themselves of the application software programs are notdescribed here since they are known from the state of the art. Thesoftware programs downloaded and stored according to the invention arein fact equivalent to those stored in general in non-volatile memoriesin receivers/decoders. In the conventional receiving boxes of the stateof the art, the application programs not being made available to thereceiver continuously on an accessible channel, it is necessary for theboxes themselves to contain the major part of the application programsin a non-volatile memory in order not to lose them each time they aredisconnected for example. This involves having a large non-volatilememory which increases when the number of functionalities of thereceiver increases, and this kind of memory is expensive.

According to FIG. 2, a receiving box is a receiver STB according to theinvention when it includes connection means CNX for, when so-calledsupply events occur, connecting said receiver STB to at least oneso-called program transportation channel PGC. Said channel PGCconstitutes transportation means belonging to said network NET. Theso-called transportation channel is typically the equivalent of atelevision channel in one advantageous embodiment. The frequency of thischannel (or the frequency of the channels which will serve as programchannels in the event of a plurality of program channels) are forexample loaded in the non-volatile memory NVM during phases of producingand configuring the receiver STB, by means of an EJTAG or RS232 genericserial interface. The program transportation channel PGC conveys atleast one continuous data stream P(SW), which is a content coded in saidformat including a software program SW coded repetitively in a loop fromthe transmission station to the receiver STB. The data stream P(SW) istransported according to the transportation format on said programtransportation channel PGC. According to the invention, the receiverincludes connection means CNX depicted in the schematic form of a switchwith positions 0 and 1 connected to said program transportation channelPGC, decoding means DEC and storage means VME which are controlled bycontrol means CNT controlled by a so-called supply program SPG stored ina non-volatile memory NVM. When the connection is established, that isto say, here, when the connection means CNX are switched to position 1,under the control of control means CNT controlled by the so-calledsupply program SPG, the receiver STB according to the invention readsthe continuous data stream P(SW) on the so-called program channel PGC.The reading can be carried out either on a single channel or on severalchannels at the same time or following each other. If the reading iscarried out on several channels, the same number of connection means canbe used for implementing the invention. The decoding means will then beconfigured for effecting a decoding of the data present on the channelsread. In order to simplify the description of the invention, FIG. 2 ispresented with a single channel. The decoding means DEC of the saidcontinuous stream of data P(SW) decode the software program SW. As thesoftware program or programs transported on said program transportationchannel are sent in a loop, the decoding means manage, whatever the timewhen the connection means are switched to position 1, to read all ofsaid software program or programs. The receiver STB according to theinvention includes storage means in the form of at least one volatilememory VME for then storing said software program SW.

In one advantageous embodiment of the invention, the receiver accordingto the invention includes conditional access means ACM intended tofunction in collaboration with conditional access codes AC[n,p] sentover the network by the transmission station. These codes AC[n,p] sentby the transmission station in the data stream over the network areintended to enable decoding in a given receiver n of a content p, whichmay in particular be a data stream P(SW) including a software program.Means known from the state of the art are here advantageously used(standard DVB, standing for “Digital Video Broadcasting”, EMM, standingfor “Entitlement Management Messages” and ECM, standing for “EntitlementControl Messages”, mechanisms, for example). Any other conditionalaccess management mechanism can however be used. These conditionalaccess means enable or not, by means of control means CNT, thefunctioning of the decoding means DEC for decoding a content P(SW)including a given software program SW, read on the program channel bythe receiver STB bearing the number n.

In a preferred embodiment of the invention, the receiver includes onlyone non-volatile memory NVM present in the receiver STB. This singlenon-volatile memory NVM includes the supply program to the exclusion ofthe application software programs. The software programs SW downloadedand stored in volatile memory include, according to this embodiment, allthe application software programs necessary, in the receiver STB, forthe processing of the data of the contents received by the receiver STBin said format. The volatile memory is an element always present in thestate of the art in a receiver intended for processing at least onecontent sent in a transportation format by a transmission station. Thisvolatile memory serves at least for the execution of the various codesnecessary for the functioning of the receiver. The additional cost ofimplementing this memory in a receiver according to the invention istherefore zero, which makes the final receiver very inexpensive andparticularly advantageous since it possesses the same functions as amore expensive receiver, by virtue of the downloaded applicationprograms. In addition a receiver according to the invention can easilybe modified by the transmission station according to the intention ofthe manager of all the receivers and/or according to the intention ofthe user, who can pay to have additional functions added, an additionfacilitated by the invention.

FIG. 3 is a schematic diagram of a method according to the invention, amethod explaining the functioning of the various means present in areceiver according to the invention and described above. This method isimplemented by software and/or hardware means implemented on anon-volatile memory NVM (for example a ROM memory). These softwareand/or hardware means constitute a supply program intended to prompt thevarious means according to the invention to function in a certain waywhich will be described by the method according to the inventionfollowing the advent of an event EV and according to said event EV. Theimplementation according to the invention of said supply program on anon-volatile memory NVM has the advantage that this supply program canbe activated permanently in the non-volatile memory NVM in the receiveraccording to the invention and that by itself the supply program will becapable of allowing the downloading of application programs necessaryfor controlling the receiver. These application programs downloaded andthen stored in volatile memory are in fact lost whenever the volatilememories are erased, for example by a loss of power.

There are many ways of implementing the functional entities presented inthe steps of a method according to the invention by software and/orhardware means accessible to a person skilled in the art. This is whyFIG. 3 is schematic. Thus, although the Figures show various functionalentities implemented by various units, this does not exclude severalfunctional entities being present in a single software and/or hardwaremeans. Nor does this exclude a combination of software and/or hardwaremeans making it possible to produce a functional entity.

According to the method of the invention, an event EV triggers the startof a method generated by the so-called supply program, depicted overallin FIG. 3. The supply events EV may for example be the connection of thereceiver to the mains or the start or end of a standby period, or asignal coming from the transmission station for supplying the receiverwith a new software program or possibly a new version of a softwareprogram for replacing a software program previously stored in memory inthe receiver but superceded. Whatever the type of event EV occurring, aconnection step CNX triggering the connection means of the receiver iscontrolled by the supply program and the switch is then switched toposition 1 if it was not already there. Once the connection means CNXare in position 1, the receiver can read the continuous data streamtransported over at least one so-called program channel PGC. Next adecoding step DEC is performed on the coded data stream read by thedecoding means. The authorization to perform the decoding step DEC canbe granted according to a conditional access management step ACSimplemented as described in the description of FIG. 2. A conditionalaccess management step ACS is therefore advantageously performed bymeans of the reception of conditional access information AC[n,P(SW)],said management step ACS giving or not authorization AUT[SW] at thedecoding step DEC for the content P(SW). A substep CHK of checking thedownloading is implemented in the decoding step DEC. This checking stepadvantageously checks whether there is an error in the downloadedprogram and checks whether the downloaded program is complete. Means ofchecking the data stream according to the state of the art can beimplemented here (checking of signatures, use of a data packet with ahead element according to various standards, for example MPEG etc). Ifthe downloaded software program is indeed downloaded and/or is complete,a command is sent by the so-called supply program to the connectionmeans CNX in order to change them to position 0, if the data includingthe downloaded software program include errors and/or do not constitutethe complete software program, a command CNX=1 makes it possible to keepthe connection means in position 1 until the software program isdownloaded correctly and fully. A step STR of storing the softwareprogram in a volatile memory of the receiver is then performed. Thedownloaded software program can thus be used in the content processingmeans EXP in the manner disclosed above.

The decoding step can advantageously include a substep EVA of evaluatingthe version of the program transported by the data stream and comparingat least one version of a software program already stored in thereceiver. As the software program or programs transported on saidprogram transportation channel are sent in a loop, the decoding meansmanage, whatever the time when the connection means are switched toposition 1, to evaluate which is the version present for a said programon the program transportation channel. If the version on the programtransportation channel is the same as a version already stored (case Y),a command CNX=0 is sent to the connection means in order to switch themto position 0. If the version is different or the corresponding programabsent (case N), the data stream is sent in a decoding step DEC similarto that described above. The program is then stored in a volatile memoryin a storage step STR similar to that described previously. This avoidsthe software programs already stored being downloaded once again. Thiscould in particular be the case when the supply event is a signal comingfrom the transmission station for supplying the receiver with a newsoftware program or possibly a new version of a software program forreplacing a software program previously stored in memory in the receiverbut superceded. This signal is for example a message from thetransmission station informing it for example that a new version of agiven software program is available and should be loaded onto thereceiver or that a specific application program for which the user haspaid is available on a program transportation channel and must be loadedby the receiver. Such an indication may be made periodically, forexample each hour. Such messages sent over the network force thereceiver to download the corresponding programs. However, if thereceiver has already received such a message and has already downloadedthe version or the software program, it is useful to carry out a test onthe nature of the version or the presence of the program to bedownloaded. An order of magnitude of the duration of downloading of theprograms essential to the basic functioning of a receiver/decoder(set-top box) on a conventional digital data transportation channel isaround one second, which makes the invention highly advantageous.

FIG. 4 is a schematic diagram of a transmission station BES according tothe invention. As seen previously, said station HES is implemented inrelation to a program transmitter BP. The transmission station is alsogenerally connected to a database RMD in which there are listed theaccess rights of the various items of electronic receivers receivingcontents p coming from the transmission station HES. These access rightstake the form of an access code AC[n,p] peculiar to the content p and tothe receiver n connected to the network NET connected to thetransmission station HES. The access rights read in the database RMD areconverted into access codes AC[n,p] in a conversion module TRF.According to the invention, the downloaded software programs SW caneither be stored in a database SLB in said transmission station HES, orbe received in the form of content p coming from a transmitter BP. Inall cases, these software programs are sent to coding means COD whichcode in particular the programs SW as a data stream P(SW), and then intransmission means TM which transmit the various coded data to thetransportation means NET and in particular the data stream P(SW) to theprogram transportation channel of the network NET. The transmissionmeans TM also advantageously receive the access codes AC[n,p], somecontents p of which are, according to one advantageous embodiment of theinvention, such that p=P(SW). A conditional access to said programtransported on the program transportation channel for the receiver istherefore implemented by virtue of such access codes in thisadvantageous embodiment. All these elements implementing a conditionalaccess control to the programs constitute a software management systemby means of which the transmission station can re-update and manage thedistribution of software programs on a stock of receivers. This isbecause such a system manages the various software programs associatedwith the various items of electronic receiver according to theinvention. For example, an access code for the data stream P(SW) isinserted for each of the receiving boxes whose owner has paid to receivesaid software program SW. The content of these access codes may bevariable over time, in particular the various items of informationcontained in a code can be sent at different periodicities. This accesscode is compatible with the known receiving box identification systems(identifying number of the receiver for example) and/or advantageouslyuses the existing standards (DVB, standing for “Digital VideoBroadcasting”, EMM, standing for “Entitlement Management Messages” andECM, standing for “Entitlement Control Messages” mechanisms forexample). For example, the book “Digital Television and MPEG-1, MPEG-2,European DVB System” by Hervé Benoit, published by DUNOD, describesthese identification systems. In particular, the Simulcrypt DVB standarddescribed in particular in the above-mentioned book makes it possible totransport the content p only once and scrambled in only one way for allthe receiving boxes connected, and hence an appreciable saving inbandwidth. A management of this type is peculiar to the invention since,when the downloading is carried out at the request of the receiver, suchmanagement is unnecessary. As the program sent in a loop over theprogram transportation channel must be available continuously for allthe receivers having authorization, it is necessary to send access codeswith a frequency which is advantageously higher than that normally usedfor conventional contents: audio and/or video for example. A period of amaximum of 10 seconds is desirable for the user. This is possible withfairly small access codes in order to take up the bandwidth to theminimum extent. These access codes will be numerous but they do not needto give rise to as high a level of security as for the broadcasting ofcontents which can be directly used, such as audio/video contents. Theywill consequently be lighter than those used in order for example toprotect the contents of a video program. Another principle of use of theaccess code is possible in a smart card system. This possibility issimilar to that used for pay per view. The smart card contains arewritable non-volatile memory of modest size (a few kilobits) comparedwith the size of the software program to be recovered (2 Mbytes or evenmore). This memory can be used for storing the “preauthorization” data,said data being sent at a low frequency (for example every monthaccording to the conventional subscription period). As soon as the boxis powered up, the program is recovered immediately by virtue of these“preauthorization” means stored for the given period. Such a principlecan also be implemented in a receiver which does not have a smart cardreader with a small non-volatile memory making it possible to store afew access codes AC[n,P(SW)]. The principle of “preauthorization”granted for example for one month is the same.

Although this invention has been described in accordance with theembodiments presented, a person skilled in the art will immediatelyrecognize that there exist variants to the embodiments presented andthat these variants remain within the spirit and within the scope of thepresent invention. In particular, conventional multiplexing elements onsaid program transportation channel are advantageously used for sendingseveral programs over the same program transportation channel withoutthis changing the principle according to the invention. Thus manymodifications can be made by a person skilled in the art without for allthat being excluded from the spirit and scope defined by the followingclaims.

1. A receiver intended to process at least one content sent by atransmission station via a network including transportation channelsconfigured for transporting said content, characterized in that itincludes: connection means for making a connection, when so-calledsupply events occur, with at least one so-called program transportationchannel, the program transportation channel transporting a contentincluding a continuous stream of data coming from said transmissionstation, said data including at least one software program, intended tocontrol said receiver, coded in a loop, from the transmission station tosaid receiver, means of decoding said continuous stream of data in orderto decode the software program, storage means including at least onevolatile memory for storing said software program, means of controllingthe connection, decoding and storage means controlled by a so-calledsupply program stored in a non-volatile memory.
 2. A receiver as claimedin claim 1, characterized in that at least one content is a contentincluding video and/or audio data, said receiver being intended to beconnected with an apparatus for exploiting said data.
 3. A receiver asclaimed in one of claims 1 and 2, characterized in that it also includesmeans for managing conditional access information received amongst thedata transmitted by the network to said receiver, said conditionalaccess information acting on said control means in order to enable ornot the functioning of the decoding means for at least one contentincluding a software program transported on said program transportationchannel.
 4. A receiver as claimed in any one of claims 1 to 3,characterized in that the only non-volatile memory present in thereceiver is the one which includes the supply program and in that thesoftware programs downloaded include the application software programsnecessary, in the receiver, for the processing of a content sent by thetransmission station.
 5. A station for sending at least one content toat least one receiver intended to process said content, saidtransmission station using a network including transportation channelsconfigured for transporting said content, characterized in that itincludes: means of coding a content including a software programintended to control said receiver, means of transmitting said codedsoftware program in a loop to a so-called program transportation channellike a continuous stream of data.
 6. A transmission station as claimedin claim 5, characterized in that it also includes a software programmanager for managing access of at least one receiver to at least onecontent including a software program, said manager inserting, in thedata transmitted by the network to said receiver, conditional accessinformation, said conditional access information acting on control meansin said receiver enabling or not the decoding of the content includingsaid software program.
 7. A method for downloading software programsfrom a station for sending at least one content to at least one receiverintended to process said content via a network including transportationchannels configured for transporting said content, characterized in thatit includes the steps of: connection of said receiver, when so-calledsupply events occur, with at least one so-called program transportationchannel, said program channel transporting a content including acontinuous stream of data coming from said transmission station, saiddata stream including at least one software program, intended to controlsaid receiver, coded in a loop, decoding of said continuous data streamin order to decode the software program, storage in at least onevolatile memory for storing said software program, said connection,decoding and storage steps being controlled by control means controlledby a so-called supply program stored in a non-volatile memory of saidreceiver.
 8. A method as claimed in claim 7, characterized in that itincludes a step of managing conditional access information receivedamongst the data transmitted by the network to said receiver, saidmanagement step making it possible to act on the control means in orderto enable or not the decoding step for at least one content including asoftware program transported on said program transportation channel. 9.A “computer program” product, characterized in that said “computerprogram” product comprises a set of instructions which, when it isloaded in a receiver intended to process at least one content sent by atransmission station over a network including transportation channelsconfigured for transporting said data as claimed in one of claims 1 to4, causes the receiver to perform one or more steps of the methodclaimed in one of claims 7 and
 8. 10. A signal including digital data,intended to be transported on a so-called program transportation channelfrom a transmission station to at least one receiver, characterized inthat said digital data comprise at least one content including asoftware program, intended to control said apparatus, sent coded and ina loop by said transmission station.